At the final whistle, the body language of the players told everyone what it meant. These were the moments Manchester City will treasure, enjoying the view from the top of the Premier League, basking in a rare form of euphoria. Roberto Mancini could be seen roaring to the skies. Vincent Kompany, the scorer of the decisive goal, was on his knees, pumping his fists.

They knew at that moment that the title race had swung significantly in their favour, leaving them on the brink of their first league championship since 1968. Three weeks ago, this City team had lost at Arsenal and a five-point lead at the top of the table had become an eight-point deficit in little more than a month. Now, once again, they are back at the summit, with only two games left. Manchester United had been anaemic and, at the end, Sir Alex Ferguson's players just stood around, unsure what to do with themselves, like car-crash victims on the hard shoulder.

It was the first time in three years that United had not managed a solitary shot on target in a league fixture and they picked a bad time to lose their way.

"City's cracking up," their supporters had been singing a few weeks ago.

One bookmaker had paid out on United winning their 20th title on 4 April, not long after the first "Champ20ns" T-shirts had appeared. By his own admission, Mancini's position was up for review. "Football is crazy," he said after an exhausting night. "But we deserve this."

United have lost to Wigan Athletic, surrendered a 4-2 lead at home to Everton and they came off the pitch here after a night when the opposition goalkeeper, Joe Hart, was barely required to get a scuff of dirt on his shorts. Ferguson and Mancini were nose to nose at one point in a row that has, almost certainly, blown a gaping hole in their relationship. Ferguson tried to prolong the argument afterwards, complaining that Mancini "was badgering the officials all game". The Italian's eyes lit up when he heard that one. "He doesn't talk with the fourth official?" he asked, heavy with sarcasm. "The referee? Never?"

Mancini did not milk the moment too much, though. "It's not finished," he maintained, pointing out his team still have to go to Newcastle United on Sunday before ending the season against Queens Park Rangers. "One team that's playing to get into the Champions League and one that's fighting relegation. If we think it's finished, it's a big mistake."

All the same, it was difficult not to leave this stadium without the sense that City now have all the momentum. "We never tested their goalkeeper," Ferguson said. "Our crossing was poor. We had some control of the game, but not enough. Nothing really happened."

Ferguson did not appear at the post-match press conference but there was one final twist in the form of Liam Gallagher making an impromptu appearance. "Top of the league, how about that?" he asked, as he took Mancini's seat, and inevitably he had his own view of the Mancini‑Ferguson spat? "Must have been on the whisky too much."

It was a surreal end to a wild, chaotic night that had used up so many emotions. This was the 163rd time these clubs have met, but never before has this occasion carried such significance or meaning. By the end, City could loosely lay claim to another famous supporter: Diego Maradona, sitting high in the Colin Bell stand, roaring his approval as his son-in-law, Sergio Agüero, menaced his opponents.

For long spells it was football played at the speed of ice-hockey. There have been far better games this season but perhaps none with more tension and when it is this fast and frenetic it is inevitable that passes are going to be misplaced and decisions rushed.

The opening 45 minutes, in particular, lacked real goalmouth drama or anything even approaching finesse. Then the electronic board was held up to show there would be two minutes added on. David Silva's corner was delivered with pace and just the right trajectory. Kompany was the one player in the penalty area to be decisive. Rio Ferdinand did not react.

Chris Smalling was too late and suddenly the ball was in the net and Kompany was running to the far corner to celebrate. "It was a bad time to lose a goal," Ferguson said. "If you lose a goal from a set‑piece at this level, you have only yourselves to blame."

Others will question whether this was one of those nights when Ferguson simply got it wrong himself. His team were set up in the formation that Ferguson likes to operate in Europe, when he is happy to use ploys of conservatism. Except, of course, United have had a pretty shocking time on their foreign excursions this season.

"We wanted to win and they wanted a draw," Mancini said. "They had all their players behind the ball. That is the difference. We wanted to win, we played better and we took our chance." It was rare to hear an opposition manager talking about United in these terms. Mancini was once castigated for being too defensive; now we had him offering critical analysis of a manager who has always prided himself on setting up teams to attack and penetrate.

What Ferguson could never have imagined was that his side would be so utterly blunt and devoid of ideas. Briefly, all the pent-up frustration came to the surface, sparked by a scything challenge from one substitute, Nigel de Jong, on another, Danny Welbeck. "He told me some kind words," a smiling Mancini said of that moment when the two managers had to be held apart. At one point Mancini was making yap-yap gestures with his hand to indicate that Ferguson did too much talking. Their relationship might not recover from that moment but Ferguson, one senses, has bigger issues to contemplate. The banner here said: "The Noisy Neighbours are Getting Louder, Alex."